UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS 

COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 
BERKELEY,  CALIFORNIA 


IRRIGATION  OF  RICE  IN 
CALIFORNIA 


BY 

RALPH    D.  ROBERTSON 

Irrigation  Engineer,  Irrigation  Investigations,  Office  of  Public  Roads  and  Rural  Engineering 
U.  S.  Department  of  Agriculture 


(Based  on  work  done  at  various  periods  during  the  years  1913-1916  in 
cooperation  with  the  Office  of  Public  Eoads  and  Eural  Engineering,  U.  S.  De- 
partment of  Agriculture,  the  California  State  Department  of  Engineering,  the 
Office  of  Cereal  Investigations  of  the  Bureau  of  Plant  Industry  of  the  IT.  S. 
Department  of  Agriculture,,  and  the  California  State  Water  Commission.) 


BULLETIN  No.  279 

May,  1917 


UNIVERSITY   OF  CALIFORNIA   PRESS 

BERKELEY 

1917 


Benjamin  Ide  Wheeler,  President  of  the  University. 

EXPERIMENT  STATION  STAFF 

HEADS    OF   DIVISIONS 

Thomas  Forsyth  Hunt,  Director. 

Edward  J.  Wickson,  Horticulture    (Emeritus). 

Herbert  J.  Webber,  Director  Citrus  Experiment  Station;   Plant  Breeding. 

Hubert  E.  Van  Norman,  Vice-Director;  Dairy  Management. 

William  A.   Setchell,  Botany. 

Myer  E.  Jaffa,  Nutrition. 

Robert  H.  Loughridge,  Soil  Chemistry  and  Physics   (Emeritus). 

Charles  W.  Woodworth,  Entomology. 

Ralph  E.  Smith,  Plant  Pathology. 

J.  Eliot  Coit,  Citriculture. 

John  W.  Gilmore,  Agronomy. 

Charles  F.  Shaw,  Soil  Technology. 

John  W.  Gregg,  Landscape  Gardening  and  Floriculture. 

Frederic  T.  Bioletti,  Viticulture  and  Enology. 

Warren  T.  Clarke,  Agricultural  Extension. 

John  S.  Burd,  Agricultural  Chemistry. 

Charles  B.  Lipman,  Soil  Chemistry  and  Bacteriology. 

Clarence  M.  Haring,  Veterinary  Science  and  Bacteriology. 

Ernest  B.  Babcock,  Genetics. 

Gordon  H.  True,  Animal  Husbandry. 

James  T.  Barrett,  Plant  Pathology. 

Fritz  W.  Woll,  Animal  Nutrition. 
*A.  V.  Stubenrauch,  Pomology. 

Walter  Mulford,  Forestry. 

W.  P.  Kelley,  Agricultural  Chemistry. 

H.  J.  Quayle,  Entomology. 

Elwood  Mead,  Rural  Institutions. 

J.  B.  Davidson,  Agricultural  Engineering. 

H.  S.  Reed,  Plant  Physiology. 

D.  T.  Mason,  Forestry. 

William  G.  Hummel,  Agricultural  Education. 

John  E.  Dougherty,  Poultry  Husbandry. 

S.  S.  Rogers,  Olericulture, 
f  Frank  Adams,  Irrigation  Investigations. 

H.  S.  Baird,  Dairy  Industry. 

David  N.  Morgan,  Assistant  to  the  Director. 

Mrs.  D.  L.  Bunnell,  Librarian. 

IRRIGATION  INVESTIGATIONS 

(In  cooperation  with  Office  of  Public  Roads  and  Rural  Engineering,  U.  S.  Depart- 
ment of  Agriculture,  and  State  Engineering  Department  of  California) 

Frank  Adams  S.  H.  Beckett 

H.  A.  Wads  worth 

Samuel  Fortier,  Chief  of  Irrigation  Investigations,  Office  of  Public  Roads  and 

Rural   Engineering. 
W.  F.  McClure,  State  Engineer  of  California. 


*  Died  February  12,  1917. 

f  In  co-operation  with   office   of  Public   Roads  and   Rural   Engineering,   U.   S. 
Department  of  Agriculture. 


IRRIGATION  OF  RICE  IN  CALIFORNIA 

By  EALPH  D.  ROBERTSON 


CONTENTS 

PAGE 

Introduction  : 254 

Water  Supply  and  Its  Use 254 

Preparation   of   Land 256 

Gates  260 

Application  of  Water 260 

Duty   of    Water 264 

Drainage  267 

Experiments    in    Rice    Irrigation 268 

Summary 270 

TABLES 

Table  1. — Summary  of  Measurements  of  Duty  of  Water  for  Rice  on  Eighteen 
Fields  in  Sacramento  Valley,  California,   1916 262 

Table  2. — Results  of  Measurements  of  the  Use  of  Water  on  the  Adams  Rice 
Field  near  Biggs,  1914,  1915,  and  1916 265 

Table  3. — Effect  of  Irrigation  Methods  and  Treatment  on  Yields  at  Biggs 
Rice  Field  Station  of  the  Bureau  of  Plant  Industry,  U.  S.  Department 
of  Agriculture,   1914,   1915,   and  1916 269 


ILLUSTRATIONS 

Figure  1. — 160-acre  Rice  Field,  Showing  Good  Arrangement  of  Supply, 
Drainage  Ditch,  and  Contour  Levees 257 

Figure  2. — Making  Levee  in  Rice  Field  with  Tractor  and  Checker  in  Sacra- 
mento   Valley,    California 258 

Figure  3. — Homemade  Checker  or  Levee  Ridger  as  Used  in  Rice  Fields  in 
Sacramento  Valley,   California 259 

Figure  4. — Heavy  Drag  or  Leveller  used  in  Preparing  Rice  Land  for  Irri- 
gation in  Sacramento  Valley 260 

Figure  5. — A  Satisfactory  Gate  for  Use  in  Inside  Rice  Levees 261 

Figure  6. — Rectangular  Weir  and  Water  Register  used  for  Measuring  Irri- 
gation Water  on  Adams  Rice  Field  near  Biggs,  California 266 

Figure  7. — One-fifth  Acre  Plat  on  Rice  Experiment  Station  near  Biggs,  Cali- 
fornia, on  which  Submergence  was  Begun  Thirty  Days  after  Emergence 
of  Plants  268 


254  UNIVERSITY  OF   CALIFORNIA EXPERIMENT  STATION 


INTRODUCTION 

The  purpose  of  this  bulletin  is  to  describe  the  irrigation  of  rice 
in  California,  principally  in  the  Sacramento  Valley,  where  about  95 
per  cent  of  the  California  crop  was  grown  in  1916.  Descriptions  are 
presented  of  the  methods  of  preparing  land  and  of  the  implements 
used,  together  with  such  data  regarding  use  of  water  on  rice  as  will 
cover  in  general  the  range  of  questions  that  most  frequently  occur  to 
prospective  rice  growers  in  California.  In  addition  to  data  gathered 
on  rice  farms  throughout  the  Sacramento  and  the  San  Joaquin  val- 
leys, information  is  presented  that  has  been  gathered  at  the  Biggs 
rice  field  station  of  the  Bureau  of  Plant  Industry,  U.  S.  Department 
of  Agriculture,  where  cooperative  irrigation  experiments  were  con- 
ducted during  the  years  1914,  1915,  and  1916.  The  introduction  of 
rice  into  California  agriculture  has  stimulated  irrigation  development 
and  the  main  increase  in  the  irrigated  area  of  the  Sacramento  Valley 
the  past  few  years  has  been  due  to  the  planting  of  this  crop. 

Rice  in  the  Sacramento  Valley  has  served  a  two-fold  purpose  of 
utilizing  land  heretofore  not  used  except  for  scanty  pasture  or  on 
which  grain  growing  has  been  declining  through  decreased  produc- 
tion, and  of  providing  a  means  of  utilizing  the  waters  of  irrigation 
systems  which  had  been  constructed  but  which  had  not  been  fully 
developed  on  account  of  lack  of  settlers.  As  is  to  be  expected,  the 
industry  has  attracted  people  from  Japan,  China,  and  India,  where 
rice  is  one  of  the  principal  crops  grown,  as  well  as  people  from  the 
rice  sections  of  Arkansas,  Louisiana,  and  Texas.  In  many  instances 
these  settlers  from  other  states  or  foreign  countries  have  introduced 
some  customs  or  practices  common  to  their  old  environments,  but  find 
in  California  peculiar  soil  or  climatic  conditions  that  may  call  for 
entirely  new  methods.  In  view  of  this,  a  description  of  methods  found 
best  suited  to  California  should  be  of  value. 

WATER  SUPPLY  AND  ITS  USE 

Approximately  67,000  acres  of  rice  were  irrigated  in  California 
in  1916.  Of  this  area  about  29,500  acres  were  irrigated  from  Sacra- 
mento River,  about  24,000  acres  from  Feather  River,  about  9800  acres 
from  other  streams,  and  about  3700  acres  with  water  pumped  from 
wells.  The  first  commercial  crop  of  rice  in  California  was  grown  in 
1912  on  1400  acres,  and  the  area  in  1916  was  more  than  twice  that 
planted  in  1915. 

The  Sutter-Butte  Canal,  which  takes  its  supply  from  Feather 
River  about  ten  miles  above  Gridley,  served  the  largest  area  of  rice 


IRRIGATION  OF  RICE  IN   CALIFORNIA  255 

in  Sacramento  Valley  in  1916,  amounting  to  17,000  acres.  The  West- 
ern Canal,  which  heads  in  Feather  River  shortly  above  Sutter-Butte 
Canal,  served  5500  acres.  The  Sacramento  Valley  West  Side  Canal, 
which  derives  its  supply  from  Sacramento  River,  supplied  water  to 
8500  acres  in  Glenn  and  Colusa  counties.  The  Yolo  Water  and  Power 
Canal,  diverting  from  Cache  Creek,  irrigated  about  6000  acres.  Other 
large  enterprises,  which  obtained  water  by  pumping  from  Sacramento 
River,  were  the  Moulton  Irrigated  Land  Company,  California  Land 
and  Rice  Products  Company,  Cheney  Slough  Irrigation  Company, 
Mallon-Blevins  Company,  and  River  Gardens  Farms  Company. 

The  only  canal  company  in  the  Sacramento  Valley  serving  water 
for  rice  irrigation  which  has  as  yet  sold  water  on  an  acre-foot  basis  is 
the  Yolo  Water  and  Power  Company,  which  charges  $1.50  per  acre- 
foot.  The  Sutter-Butte  Canal  Company  has  furnished  water  for  rice 
to  lands  having  water  rights  at  an  annual  charge  of  $5  per  acre. 
Recent  contracts  made  by  this  company  are  on  the  basis  of  $7  per 
acre,  with  reimbursements  to  the  water  user  for  the  construction  of 
ditches  and  for  rights  of  way,  provided  water  has  been  used  for 
more  than  two  successive  years.  The  amount  of  water  called  for  in 
the  Sutter-Butte  contracts  is  at  the  rate  of  one  cubic  foot  per  second 
for  each  53  ys  acres.  The  Sacramento  Valley  West  Side  Canal  Com- 
pany, by  authority  of  the  California  State  Railroad  Commission, 
charged  $7  per  acre  for  rice.  For  this  charge  the  water  user  was 
entitled  to  five  acre-feet  of  water  per  acre,  additional  amounts  to  be 
charged  for  at  the  rate  of  $1.50  per  acre-foot.  However,  no  cases 
are  known  in  which  water  used  in  excess  of  five  acre-feet  was 
charged  for. 

Pumping  from  wells  for  rice  irrigation  in  California  has  been 
chiefly  resorted  to  in  the  San  Joaquin  Valley,  but  to  a  limited  extent 
also  in  the  Sacramento  Valley.  There  are  many  opportunities  for 
this  type  of  development  where  water  can  be  obtained  by  low  lifts 
from  wells  or  streams  either  for  the  entire  season  or  for  a  portion 
of  the  season  in  supplementing  a  gravity  supply.  Owing  to  the  large 
water-requirements  of  rice  and  the  steady  demand  for  water  through- 
out a  long  season,  wells  should  be  thoroughly  tested  before  rice  is 
planted  and  failures  can  be  avoided  by  keeping  the  acreage  commen- 
surate with  the  water  supply.  The  charge  for  electric  power  in  the 
Tulare  and  Kern  sections  of  the  San  Joaquin  Valley  is  $42.30  per 
horsepower  per  annum  and  in  the  Sacramento  Valley  the  usual  rate 
for  the  smaller  plants  is  approximately  two  to  two  and  one-half  cents 
per  kilowatt  hour,  depending  upon  the  size  of  the  plant  and  the 
character  of  the  contract.     Engines  burning  cheap  oil  or  distillate 


256  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

may  also  be  used.  Centrifugal  pumps,  on  account  of  their  adapt- 
ability and  ease  of  operation,  are  the  most  common  type  of  pump. 
Twelve-inch  wells  are  commonly  used,  and  the  usual  contract  price 
for  drilling  is  $1.50  per  foot  for  the  first  100  feet  and  an  increase  of 
fifty  cents  a  foot  for  each  additional  fifty  feet. 

A  study  of  reports  of  the  United  States  Geological  Survey  will 
assist  those  who  propose  to  engage  in  pumping  from  wells.1 

PEEPARATION  OF  LAND 

Land  is  prepared  for  rice  in  contour  checks,  the  difference  in 
elevation  between  checks  varying  from  .25  to  .30  foot  where  the 
slope  of  the  country  is  from  two  feet  to  five  feet  per  mile.  Usually  a 
surveyor  is  employed  to  lay  out  the  field  and  the  cost  of  surveying 
amounts  to  from  twenty-five  to  fifty  cents  per  acre.  One  of  the  most 
rapid  methods  of  locating  the  contours,  in  which  no  stakes  are  re- 
quired, is  to  have  the  rodman  mark  the  location  by  shaking  a  small 
amount  of  lime  on  the  ground  from  a  sack.  After  a  few  points  have 
been  located  on  a  contour,  a  plow  team  connects  the  points  by  plow- 
ing four  to  six  furrows  which  form  the  base  of  the  levee.  Sometimes 
the  contours  or  field  levees  are  marked  by  lath  stakes,  and  to  avoid 
confusion  where  the  contours  come  close  together  a  good  plan  is  to 
tie  a  rag  of  a  certain  color  on  the  stakes  marking  one  contour  and 
to  use  a  rag  of  a  different  color  on  another  contour.  Sharp  turns  in 
the  levees  should  be  avoided  wherever  possible. 

Figure  1  shows  a  160-acre  rice  field  prepared  for  irrigation.  The 
head  ditch  extends  along  the  north  line  or  upper  end  of  the  field 
and  follows  part  way  along  the  east  side.  A  drainage  ditch  is  pro- 
vided at  the  lower  end  along  the  south  side  of  the  field,  and  also 
along  the  west  side.  The  field  is  divided  into  eleven  checks,  the  con- 
tour interval  or  difference  in  elevation  between  checks  being  .30  foot. 
It  will  be  noted  that  there  is  a  direct  inlet  and  outlet  provided  for  each 
check  and  also  that  several  gates  are  placed  in  interior  levees  to 
admit  water  from  one  check  to  another.  This  arrangement  provides 
good  control  of  water  from  the  head  ditch  and  also  offers  advantages 
in  draining  the  field.  In  case  of  a  break  in  the  ditch  or  levees  the 
water  may  be  quickly  removed  and  repairs  can  also  be  made  in  one 
part  of  the  field  without  interrupting  the  service  in  another. 

The  outside  levee  is  made  stronger  than  the  interior  or  field  levees 
and  should  have  a  base  of  six  to  eight  feet  and  a  height  of  1.5  to  2.5 

i  Ground  Water  for  Irrigation  in  the  Sacramento  Valley,  California :  U.  S. 
Geol.  Survey  Water-Supply  Paper  375a.  Ground  Water  in  the  San  Joaquin 
Valley,  California:    U.  S.  Geol.  Survey,  Water  Supply  Paper  398. 


IRRIGATION  OF  RICE  IN  CALIFORNIA 


257 


feet.  There  is  probably  no  more  satisfactory  implement  for  making 
a  strong  levee  than  the  Fresno  scraper,  because  the  team  in  passing 
back  and  forth  over  the  freshly  moved  earth  packs  it  down  securely. 
The  interior  levees  are  more  commonly  made  with  a  checker  or  ridger 
drawn  by  a  tractor.  Figure  2  shows  a  checker  in  use.  This  imple- 
ment is  provided  with  a  device  for  raising  or  lowering  the  rear  end, 


ttAIN    SUPPLY    LATER RL 


Outlet/gates 


DRAINAGE.       DrrCH    - 

Fig.  1. — 160-acre  rice  field,  showing  good  arrangement  of  supply,  drainage  ditch, 

and  contour  levees. 


enabling  the  operator  to  regulate  the  size  of  the  levee.  More  often  a 
simple  home-made  implement  is  used  such  as  is  shown  in  figure  3, 
the  cost  of  which  is  about  $50.  The  runners  for  sides  are  made  of 
three-inch  by  twelve-inch  plank  twenty  feet  in  length  and  are  lined 
with  steel.  The  front  end  is  made  ten  feet  wide  on  the  bottom  and  the 
rear  end  is  three  feet  wide  on  the  bottom.  The  sides  are  made  two 
feet  high  and  are  set  on  a  batten  of  one-fourth  to  one,  the  tops  sloping 


258 


UNIVERSITY  OF   CALIFORNIA EXPERIMENT  STATION 


outward.  This  implement  makes  a  levee  having  a  base  of  about  five 
feet  and  a  height  when  settled  of  about  twelve  inches.  On  fairly  even 
ground  a  crew  of  two  or  three  men  with  a  tractor  frequently  check 
150  acres  or  more  per  day.  Often  the  work  is  contracted  and  a  com- 
mon price  paid  is  $50  per  day  for  the  use  of  the  tractor  and  checker. 
Sometimes  the  levees  are  made  with  a  "V"  crowder  which  is  also 
widely  used  in  making  field  ditches.  Recently  a  "V"  made  of  steel 
and  reversible  has  come  into  use. 

In  most  sections  no  attempt  has  been  made  to  level  or  grade  the 
land  within  a  check,  the  preparation  of  land  consisting  mainly  in 
building   the   supply   ditches   and   constructing   the   levees.      In   the 


Fig.  2. — Making  levee  in  rice  field  with  tractor  and  checker  in  Sacramento  Valley, 

California. 


vicinity  of  Willows  large  drags  or  floats  drawn  by  tractors  are  used 
to  smooth  the  surface  after  the  land  is  plowed  (fig.  4).  It  is  doubtful 
if  much  leveling  of  land  is  justified  because  in  fields  where  knolls 
or  hummocks  have  been  removed  to  fill  in  low  places  it  has  been 
found  that  in  the  "fills"  the  plant  develops  a  rank  growth  of  straw 
and  the  heads  are  not  filled,  while  in  the  heavily-scraped  portions  of 
the  field  the  plant  is  stunted  in  growth.  On  the  other  hand  it  must 
be  kept  in  mind  that  a  uniform  depth  of  water  over  the  field  is  highly 
desirable.  If  the  depth  of  water  is  not  fairly  uniform  there  is  a 
difference  in  the  time  of  maturity  of  the  rice  and  the  yields  are  also 
affected,  as  shown  in  the  experiments  at  Biggs  reported  later  in  table 
3.  The  amount  of  work  and  expense  justified  in  preparing  the  field 
must  therefore  rest  largely  on  the  judgment  of  the  grower. 


IRRIGATION  OF  RICE  IN   CALIFORNIA 


259 


The  universal  practice  has  been  to  harvest  within  a  single  check 
on  account  of  the  obstructions  offered  to  the  passage  of  machinery 
by  the  present  type  of  field  levee.     It  is  possible  that  as  the  industry 


pi  o» 


ro— 

ELEVATION 


Fig.  3. — Homemade  checker  or  levee  ridger  as  used  in  rice  fields  in  Sacramento 

Valley,  California. 


advances  more  permanent  levees  with  a  base  of  about  ten  feet  and 
gentle  side  slopes  will  be  used.  The  advantages  of  broad  levees, 
besides  those  of  ease  and  cheapness  in  planting  and  harvesting,  are 
that  the  cultivated  area  is  increased  and  weed  growth  can  be  better 


260  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

controlled.     It  can  not  be  expected,  however,  that  the  growth  of  rice 
on  the  levees  will  yield  any  appreciable  amount. 

GATES 
Gates  are  necessary  in  the  canal  banks  to  admit  water  to  the  checks 
and  also  in  the  field  levees  for  admitting  water  from  one  check  to 
another.  The  canal  structures  are  of  the  ordinary  type  used  in  irri- 
gation, but  the  gates  in  the  field  levees  are  less  substantial  than  those 
usually  employed  for  alfalfa  irrigation.  It  is  important  to  have  the 
gates  sufficiently  wide  to  admit  the  large  heads  of  water  used  in  the 
initial  floodings.  Figure  5  shows  a  simple  form  of  wooden  gate  which 
can  be  installed  for  about  fifty  cents.     Where  the  gate  is  more  than 


Fig.   4. — Heavy   drag  or  leveller  used  in  preparing  rice  land   for   irrigation   in 

Sacramento  Valley. 

four  feet  wide  a  center  division  support  is  used.  Box  tubes  which 
are  sometimes  placed  through  the  levees  are  not  generally  satisfactory. 
The  gates  should  be  well  tamped  and  preferably  puddled  in,  at  the 
time  of  placing  them,  to  prevent  leaks. 

APPLICATION  OF  WATER 
The  irrigation  season  is  divided  into  two  main  periods.  In  the 
first  period  irrigations  are  given  to  keep  the  soil  moist,  but  without 
having  the  water  stand  on  the  field.  In  the  second  period  the  field  is 
continually  submerged.  It  has  been  found  necessary  to  irrigate  after 
planting  to  germinate  the  seed  and  to  give  enough  subsequent  water- 
ings to  maintain  growth  until  the  plant  is  from  four  to  six  inches  high. 
The  best  time  to  begin  submergence,  according  to  the  experiments 


IRRIGATION   OF  RICE  IN  CALIFORNIA 


261 


at  Biggs,  is  about  thirty  days  after  the  emergence  of  the  plant  above 
ground.  The  principal  reason  for  not  permitting  water  to  stand  on 
the  field  during  the  germination  period  is  the  danger  of  the  seed 
rotting  in  the  ground,  especially  if  weather  conditions  are  unfavor- 
able and  the  soil  is  cold.  As  a  rule,  water  should  not  be  allowed  to 
remain  on  the  land  more  than  one  or  two  days  after  the  initial  flood- 


Fig.  5. — A  satisfactory  gate  for  use  in  inside  rice  levees. 


ings.  The  use  of  heads  of  water  varying  from  two  to  five  cubic  feet 
per  second  or  more  facilitates  quick  watering  at  this  time.  During 
submergence  the  heads  need  not  be  so  large. 

In  beginning  submergence  the  water  should  be  gradually  raised 
until  an  average  depth  of  six  inches  is  attained.  Likewise  at  the 
close  of  the  submergence  period  the  water  should  be  gradually  lowered 
and  not  hurriedly  removed,  a  rapid  draining  having  a  tendency  to 
weaken  the  straw.  Care  should  be  exercised  when  draining  the  fields 
not  to  cause  injury  to  lower  areas.     Much  damage  has  resulted  to 


m 


Yield  of  paddy  rice,  sacks 
per  acre  (averaging  100 
pounds  each) 


pi  oil! 
|**  is* 


End  of 


Beginning 
of  season  .. 


g  ®  >  e  a  5  4>\  season 


g!fe|^g§|Periodof 
<j  *"*     M     [submergence 


Net  depth  applied,  feet . 


Estimated  or  measured 

surface  waste, 

acre  feet  per  acre 


Total  depth  applied,  feet 


Depth  of  water  used 
during  submergence,  feet. 


Depth  of  water  used 
prior  to  submergence,  feet 


Number  of  irrigations 
prior  to  submergence .. 


6D  hj  cS  eg 

S  •-   (CO 


Total 


Period  of 
submergence 

Prior  to 
submergence 


03   ^V 


stLsss 

I— I  cc 


Q^H 


s  ^ 

o  s 


© 

in 

o 

m 

O 

co 

co" 

m 
in 

© 
cm' 

© 

in 

© 

CO 

© 

CO 

lC 

m' 

in 

in 

m 

CO 

00 
CO 

© 

CO 

o 
cm' 

o 

-+ 

T* 

CM 

CM 

m 

CM 

CO 

in 

m 

m 

CO 

© 

00 
CO 

CO 
CM 

© 

CM 

© 
CO 

- 

- 

- 

o 

00 

m 

00 

CO 
00 

00 

l> 

00 

in 

© 

CO 

© 

CO' 

CO 

m 

00 

in 

CM 
<M 

CO 

CM 

CO 

m" 

CM 
© 

oc 
in 

CO 

m 

© 

CO 
CM 

cm' 

© 
CO 
CM 

N 

m 

© 
o 

- 

- 

- 

© 

fr- 

-* 

■* 

m 

m 

- 

- 

- 

o 
t- 

t- 

CO 

| 

© 
00 

m 
m 

CD 
00 

CO 

"■* 

CM 

OB 

CM 

g 

o 

- 

- 

- 

CD 

m 

CM 

m 

1- 

co 

m 
<* 

o 

CO 

m 

- 

- 

- 

CM  (M 


m  <-h 


Eh     co 
02     <M 


>   c« 

S   " 


=e!H     *2     ^^     *32     *2     rt2 

—    03         "^CC  ,-.    0)  r-    CD  <-    03  f-    33 

S£~  §£~  Sfc^  Sfe^-  ££_•  §k^  Z>~  5f  . 

a   ga^ga   ga^ga^ga^gs^g-S-s 

08oSc8  08«8«c8p 

W02C»C/2!Z)CCCOPh 


P"S 


a"3 
§•2 


12 


It 

2  * 


o  £     _o 
So     5 


cm  a 


m  i-h 


-CM  .rrH 


I***80  S 
ifc 


83fc» 


^5 

■  ge 

o  <»► 

gOQC 

2* 
O 


o'EH 

52;  oc 


'rSHW 


o.  •  a  « 


Ocm.  "  S  d 


rH  -^HtCO 


*»         .^      JJ5       gc»         .02       est 


© 

© 

© 

o 

© 

q 

CO 

o 

CO 

© 

CO 

1.7 

IC 

m 

lO 

1ft 

in 

o 

00 

t^- 

so 

© 

•& 

CO 

to 

CM 

00 
CM 

CO 

o 

© 

o 

© 

CO 

CM 

00 
CM 

00 

(M 

CM 

o 

CO 

O  CO 


CM  r-i 


to 
to 

o 

00 

1ft 

CO 

00 
CM 

3 

00 
CO 

o 
t- 

CO 
© 

<* 

"* 

* 

© 

00 

CM 

lO 

oc 

© 

rH  ©  rH 


r-l  © 

©  lO 

r-i  CM 


© 

© 

t- 

© 

© 

W 

lO 

© 

lO 

t~- 

CM 

© 
© 

© 

© 
© 

m 

© 

t- 

3 

00 

©  . 

s 

l> 

© 
© 

© 
© 

© 
© 

r~ 

P. 

+_, 

jj 

.u 

P 

P 

+J 

^J 

+J 

u 

u 

K 

OQ 

O 

O 

o 

02 

CO 

o 

O 

o 

0 

~7> 

"t 

r> 

2 

CM 

'rA 

CO 
CM 

CM 

© 

© 

<D 

<s 

CD 

>> 

CD 

<o 

CD 

CD 

h 

0 

a 

3 

3 

3 

3 

3 

3 

3 

3 

3 

«i 

t-s 

1-3 

»-s 

i-s 

►"3 

1-3 

i-s 

!"J 

1-1 

hH 

1_. 

00 

00 

^ 

00 

1ft 

CM 

CM 

CM 

CO 

■— I 

i — i 

r— I 

•—> 

r— i 

p— i 

, — i 

i — i 

P 

c 

;_ 

>s 

£ 

£ 

U 

a 

P. 

p. 

P. 

P 

P 

P 

P 

t; 

^ 

<j 

<! 

^H 

< 

<! 

<) 

< 

M-3 
So 

3 

co 


md    wd 


So 


>-  a 


CD 

O 

CD 
C 

CD 

O 

CD 
r<3 

o 

CD 
fit 
O 

co 

a 

i 

03 

o 

CO 

s 

03 

o 

3-eS 

P 
CD 
CD 

O     c3 

ct 

c5 

c3 

cS 

oS 

o 

©^  3    • 

<r3 

.2  o 

>> 

>> 

>> 

e3 

b 

>> 

o3 

3 

p 

3 

£ci  g® 

CS  CD   ©  "S 

o3 

cd  .a 

0 

o 

r* 

CD 

o 

u 

3 
O 

M 

CD 

o 

O 

3 
O 

o 

o 

© 

o 

P 

o 

M 
o 

o 

3 
o1 
eS 

O 

i-s 

3 

o1 

eg 

o 

p 

03 

C 

O 

3 
03 

o 

CD 

CD 
> 

>      CD 

CD      <o 

CD      « 

CO 

CO 

CO 

CO 

CO 

CO 

CO 

CO 

P>       M 

CD 

O     --2 

© 

© 

CO 

© 

© 

© 

1(0 

© 

© 

P 

J3     o 

be 

l~ 

00 

PH 

© 

~5 

X 

CM 

3 

0  -? 

CO 

o    i« 

CM 

M 

rd    o 

^< 

^^ 

9?: 

r?5 

© 

a,© 

CD  © 

© 

cH 

•-3- 

i^H 

^rn 

«&H 

3E"1 

®    - 

c?cl 

CD  00 
w    CM 

^S 

32 

*ri 

S9 

o 

iH«  2' 


i    ^    ^^    -gsz;    g£    ^    ^    f^ 

a         O         Q         o         P5         M         co 


CD 
a>     > 

%  ° 

o    P 


CO 


5  o 

.  CO  3  rt 

CD  co  03  eg 

1  °  II 

tp  ^  .2  -D 

CD  ^3  CO  •  "^ 

"S  3  «  2 

3  3  O  ^ 


co  ts 

co  .« 

CD  CO 

8  § 

w  o 


264  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

crops  on  lands  situated  below  rice  areas  by  water  drained  from  rice 
fields  at  harvest  time.  In  one  instance  many  thousands  of  dollars 
worth  of  beans  were  destroyed  in  this  way. 

There  has  been  considerable  criticism  in  the  past  from  millers  of 
California  rice,  who  claimed  that  the  rice  was  cut  before  being  fully 
matured.  When  the  heads  of  the  grain  are  well  turned  down 
the  water  should  be  cut  out  of  the  laterals.  At  this  stage  of  maturity 
most  of  the  kernels  are  beginning  to  harden.  On  the  heel  or  lower 
part  of  the  head  the  kernels  should  be  in  the  dough  stage.  After 
the  water  is  removed  it  is  usually  two  weeks  before  the  soil  is  suf- 
ficiently dry  to  permit  the  use  of  a  binder  in  harvesting  the  crop. 

The  experiments  at  Biggs  serve  to  show  the  best  manner  of  hand- 
ling the  water  on  soils  in  that  vicinity,  but  in  sections  where  the  soil 
contains  alkali  the  usual  irrigation  programme  may  have  to  be  modi- 
fied. On  alkali  lands  near  Willows  the  beneficial  effects  of  applying 
fresh  water  and  of  keeping  it  circulating  through  the  fields  were 
apparent.  Irrigators  in  that  section  hope  to  reclaim  the  land  by  fre- 
quent drainage  and  the  application  of  fresh  water.  This  method  is 
also  used  in  portions  of  San  Joaquin  Valley  on  alkali  soils,  but  where 
pumping  from  wells  is  resorted  to  the  cost  of  water  is  a  limiting 

factor. 

DUTY  OF  WATER 

Measurements  were  made  in  1916  of  the  water  used  on  eighteen 
representative  rice  fields  in  Sacramento  Valley.  This  work  was  done 
in  cooperation  with  the  California  State  Water  Commission  and  the 
results  are  summarized  in  table  l.2  Nine  of  these  fields  were  located 
on  the  west  side  of  Sacramento  Valley  in  the  vicinities  of  Willows, 
Maxwell,  and  Princeton,  and  nine  on  the  east  side  in  the  vicinities 
of  Biggs,  Richvale,  Nelson,  and  Marysville.  Ten  different  soil  types 
were  represented.  The  investigations  showed  a  wide  range  in  the 
net  amount  of  water  used,  varying  from  4.27  acre-feet  per  acre  to 
14.83  acre-feet  per  acre.  The  average  depth  applied  to  the  eighteen 
fields  was  8.23  feet  and  the  average  area  served  per  cubic  foot  per 
second  for  the  whole  season  was  forty-seven  acres.  The  difference 
in  use  was  attributed  to  numerous  factors,  the  more  important  of 
which  were  the  character  of  the  soil  and  subsoil,  preparation  of  land, 
depth  to  water  table,  proximity  of  lands  to  sloughs,  and  manner  of 
handling  water.  The  heads  of  water  used  varied  considerably  in  size, 
owing  to  the  diversity  in  the  size  of  the  fields,  but  reduced  to  an 
acreage  basis  were  fairly  uniform.  The  average  head  used  per  acre 
on  the  eighteen  fields  was   .052   cubic  foot  per  second  before  sub- 

2  See  also  Third  Eeport  of  the  State  Water  Commission  of  California. 


IRRIGATION  OF  RICE  IN   CALIFORNIA  265 

mergence  and  .034  during  submergence.  For  a  forty-acre  field  this 
would  amount  to  2.08  and  1.36  cubic  feet  per  second,  respectively. 

On  each  of  three  fields  where  less  than  five  acre-feet  per  acre  was 
applied,  the  soil  was  a  black  clay  adobe,  underlain  at  shallow  depths 
with  a  non-continuous  hardpan  with  ground  water  approximately  one 
foot  below  the  surface.  These  fields  were  well  prepared  and  the 
water  was  carefully  handled,  little  or  no  water  being  wasted.  Exces- 
sive use  was  found  on  fields  close  to  sloughs  or  on  land  with  porous 
subsoil  and  with  poorly  constructed  outside  levees. 

On  the  Adams  field  included  in  table  1,  measurements  were  made 
of  the  water  used  in  1914,  1915,  and  1916,  the  data  for  these  years 
being  given  in  table  2.  This  field  is  located  about  three  miles  north- 
west of  Biggs  and  comprises  39.5  acres  in  the  NE  %,  sec.  34,  T.  19  N, 
R.  2  E.  The  soil  is  Stockton  clay  adobe  typical  of  large  areas  utilized 
for  rice  growing  in  Butte  County. 

TABLE  2 

Results  of  Measurements  of  the  Use  of  Water  on  the  Adams  Eice  Field 
near  Biggs,  1914,  1915,  and  1916 


60 

'1  » 

03 

(3 

<H 

CD  o  o> 

u 

®  ..„  <» 

5  « 

£ 

u-*="  « 

+a^5   O 

-HS     W)    « 

u  £ 
efl.o 

a5 

®  c 

«4-l     O    1< 

O-   bO 

S3   U   ^ 

op,* 

o3  S3  C 
fe-r  cu 

o^  it 

5« 

O   63 

£s 

^fl 

fl»a 

rC-tf  a 

x^  a 

a 

0)  .Sr 
if  t* 

ft"" 

2,5 

C3   2 

CD   £ 

•0. 

O   c8 

1914 

April  29 

June  12 

October 

12 

6 

1.04 

3.61 

4.65 

1915 

April  21 

June 

9 

October 

1 

7 

1.37 

3.50 

4.87 

1916 

April  13 

June 

9 

September    30 

6 

1.01 

3.26 

4.27 

Taking  the  three-year  period,  the  average  total  depth  applied  was 
4.58  feet  and  the  average  length  of  irrigation  season  from  the  time 
of  the  first  irrigation  until  water  was  turned  off  was  167  days.  The 
field  was  planted  to  Wataribune  variety,  a  short-grain  rice  which 
comprises  the  greater  part  of  the  acreage  of  rice  in  California.  Yields 
of  approximately  6000,  4500,  and  3900  pounds  per  acre  were  obtained 
in  the  years  1914,  1915,  and  1916,  respectively.  Especial  care  was 
given  to  this  field  and  the  yields  were  above  the  average. 

The  amounts  of  water  used  on  this  field  probably  represent  the 
minimum  use  under  gravity  canals  in  Butte  County  and  show  what 
can  be  accomplished  with  careful  handling  of  water  on  well-prepared 
land. 

In  connection  with  the  above  measurements,  records  of  precipita- 
tion and  evaporation  from  a  free  water  surface  tank  were  kept  by 


266 


UNIVERSITY  OF   CALIFORNIA EXPERIMENT  STATION 


the  Bureau  of  Plant  Industry,  U.  S.  Department  of  Agriculture,  on 
the  Biggs  rice  field  station  which  adjoins  the  field. 

The  amounts  of  rainfall  and  evaporation  in  the  periods  corre- 
sponding to  the  irrigation  season  for  the  years  1914  to  1916,  inclusive, 
are  given  below : 


Year 

1914 

Precipitation 

during 

irrigation 

season, 

feet 

0.21 

Evaporation 

during 

irrigation 

season, 

feet 

2.91 

1915 

0.36 

3.17 

1916 

0.13 

3.48 

Fig.  6. — Kectangular  weir  and  water  register  used  for  measuring  irrigation  water 
on  Adams  rice  field,  near  Biggs,   California. 

Measurements  of  the  water  used  were  made  by  means  of  a  stand- 
ard contracted  weir  and  automatic  water  register  shown  in  figure  6. 
Average  heads  of  two  to  five  cubic  feet  per  second  were  used  in  the 
initial  floodings,  while  an  average  flow  of  .50  to  .75  cubic  foot  per 
second  was  continually  run  during  the  period  of  submergence. 

It  is  interesting  to  compare  the  irrigation  practice  and  data  for 
rice  growing  in  California  with  those  of  the  rice  sections  of  Arkansas, 
Louisiana,  and  Texas.3  In  those  three  principal  rice-growing  states 
all  but  2.5  per  cent  of  the  irrigated  land  in  rice  is  supplied  with  water 
by  pumping,  and  wells  afford  a  supply  for  about  one-third  of  this 
area.    For  prairie  lands  the  pumping  machinery  is  generally  designed 


IRRIGATION  OF  RICE  IN  CALIFORNIA  267 

to  provide  seven  and  one-half  gallons  of  water  per  minute  for  each 
acre  irrigated,  which  is  equivalent  to  a  flow  of  one  cubic  foot  per 
second  for  sixty  acres.  For  the  alluvial  lands  along  the  streams  ten 
gallons  of  water  per  minute  per  acre  is  provided,  while  thirty-eight 
to  forty  gallons  per  minute  per  acre  is  sometimes  required  if  the  soil 
is  a  loose,  sandy  loam,  with  a  porous  subsoil,  and  is  located  near  a 
river.  The  average  length  of  the  irrigation  season  in  the  rice  sections 
of  Arkansas,  Louisiana,  and  Texas,  extending  from  the  time  of  the 
first  application  of  water  until  it  is  removed  to  permit  harvest,  is 
about  eighty-six  days. 

The  fact  that  more  water  is  required  to  mature  rice  in  California 
than  in  the  rice  sections  of  the  south  is  ascribed  principally  to  the 
difference  in  climate.  The  nights  are  much  warmer  in  the  southern 
states  than  in  California  and  there  is  less  difference  in  the  daily 
range  of  temperature.  The  number  of  days  that  water  must  be  used 
to  mature  rice  in  California  is,  therefore,  much  greater  than  in 
Arkansas,  Louisiana,  or  Texas.  The  rainfall  during  the  irrigation 
season  in  California  is  practically  negligible,  while  in  the  southern 
states  it  may  amount  to  ten  or  twenty  inches.  The  evaporation  in 
California  is  generally  over  twice  that  in  the  south.  Fortier  reports 
that  measurements  have  been  made  of  rainfall,  evaporation,  and  the 
duty  of  water  for  irrigating  rice  on  prairie  lands  of  Louisiana,  Texas, 
and  Arkansas  for  eleven  years,  during  which  twenty-one  measure- 
ments have  been  made.4  The  averages  of  these  measurements  give 
15.74  inches  of  pumped  water  applied  to  the  land  and  17.16  inches 
of  rainfall,  and  a  loss  due  to  evaporation  from  flooded  rice  fields 
of  15.33  inches. 

DRAINAGE 

Facilities  for  drainage  are  almost  as  important  as  for  irrigation. 
The  planting  as  well  as  the  harvesting  depends  largely  upon  the 
condition  of  the  field,  and  on  heavy  clay  soils  which  naturally  dry 
out  slowly  drainage  is  a  most  important  feature.  Poor  drainage 
results  in  low  places  remaining  wet  and  not  only  delays  planting,  but 
also  impedes  the  progress  of  heavy  harvesting  machinery.  Thorough 
drainage  is  the  only  solution  for  removing  alkali  salts  and  for  reliev- 
ing water-logged  lands. 

In  sections  where  drainage  is  naturally  poor  the  growing  of  rice 
with  its  heavy  application  of  water  tends  all  the  more  to  increase  or 
intensify  the  needs  of  drainage.  Any  effective  means  of  controlling 
weeds  that  now  menace  the  rice  industry  and  conditions  that  will 

3U.  S.  Dept.  Agr.,  Farmers'  Bui.  673. 

4  Use  of  Water  in  Irrigation,  1  ed.,  p.  229. 


268 


UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 


make  possible  a  rotation  of  crops  must  depend  largely  upon  adequate 
drainage.  The  people  of  Richvale,  realizing  the  need  of  lowering  the 
water  table  which  has  risen  to  within  a  foot  of  the  surface,  recently 
voted  $150,000  for  drainage.  The  formation  of  drainage  district 
No.  833,  including  lands  west  of  Biggs  and  Gridley,  is  a  hopeful  sign 
of  meeting  the  problem  in  that  portion  of  the  valley.  The  opening 
up  of  natural  water  courses  and  the  construction  of  a  comprehensive 
drainage  system  in  keeping  with  the  flood  control  work  now  being 
undertaken  in  the  Sacramento  Valley  is  likely  to  have  an  important 
bearing  upon  the  future  of  the  rice  industry  in  California. 


Fig.  7. — One-fifth  acre  plat  on  Eice  Experiment  Station  near  Biggs,  California, 
on  which  submergence  was  begun  thirty  days  after  emergence  of  plants. 


EESULTS  OF  EXPEEIMENTS  IN  EICE  IEEIGATION 
Experiments  in  rice  irrigation  were  carried  on  for  the  years  1914 
to  1916,  inclusive,  in  co-operation  with  the  Bureau  of  Plant  Industry, 
U.  S.  Department  of  Agriculture,  on  the  Biggs  rice  field  station.  The 
objects  of  the  investigations  were  to  determine  the  effect  of  varying 
dates  of  submergence  of  land,  varying  depths  of  submergence  of  land, 
the  effect  of  no  continuous  submergence,  as  well  as  the  effects  of 
stagnant  and  slowly-changing  water.  Attention  was  also  given  to 
fluctuating  the  depth  of  water  during  submergence  to  determine  the 
effect  on  the  growth  of  the  plant.  The  tests  were  made  on  %-acre 
plats  (fig.  7)  enclosed  by  well-constructed  levees  and  arranged  so  that 


IRRIGATION  OF  RICE  IN   CALIFORNIA 


269 


they  could  be  irrigated  and  drained  separately.  The  soil  is  a  black 
clay  adobe  typical  of  lands  utilized  for  rice  growing  in  the  vicinity 
of  Biggs  and  Gridley.   Results  of  the  experiments  are  given  in  table  3. 

TABLE  3 

Effect  of  Irrigation  Methods  and  Treatment  on  Yields  at  Biggs  Eice  Field 

Station  of  the  Bureau  of  Plant  Industry,  U.  S.  Department 

of  Agriculture,  1914,  1915,  and  1916. 

Yield  per   acre,   pounds 

A 

Irrigation  treatment  1914  1915  1916  Average 
Beginning    submergence    fifteen    days    after 

emergence    of    plant 4510  3860  3750  4040 

Beginning    submergence    thirty    days    after 

emergence    of    plant 5610  4270  4020  4633 

Beginning  submergence  forty -five  days  after 
Beginning    submergence     sixty     days    after 

emergence  of  plant 5410  4100  3890  4466 

Submergence  maintained  two  inches  deep  ....  5010  4030  3620  4220 

Submergence    maintained    four    inches    deep  5490  4290  3760  4513 

Submergence  maintained  six  inches   deep  ....  5670  4510  3900  4693 

Submergence   maintained   eight   inches   deep  5220  4400  3940  4520 

Slowly    changing    water 4790  4210  3460  4153 

Stagnant    water    4940  3990  3800  4243 

No    submergence    (soil    kept    moist    by    fre- 
quent  irrigation)    2440  2480  2100  2340 

Fluctuation  of  depth 5290  4160  3690  4380 

Each  year  the  best  results  were  obtained  by  commencing  sub- 
mergence thirty  days  after  emergence  of  the  plant.  In  1914  and 
1915  the  heaviest  yields  were  secured  by  maintaining  a  uniform  depth 
of  six  inches  over  the  land  during  submergence,  but  in  1916  the  plat 
submerged  eight  inches  deep  gave  the  heaviest  yield,  although  the 
increase  in  yield  only  amounted  to  about  1  per  cent  over  the  plat 
submerged  six  inches  deep.  Where  no  water  was  held  on  the  land, 
but  the  soil  was  merely  kept  in  a  mucky  condition,  only  about  one- 
half  of  a  normal  yield  was  secured  and  the  rice  was  of  poor  quality. 
There  was  little  difference  in  the  yield  from  the  plat  which  received 
slowly-changing  water  and  from  the  plat  which  had  no  water  removed. 
No  reaction  on  the  growth  of  the  plant  was  shown  from  fluctuating 
the  depth.  In  this  experiment  a  uniform  depth  of  four  inches  was 
maintained  until  "booting"  was  noticeable.  Then  the  water  was 
lowered  to  a  depth  of  one  and  one-half  inches.  The  water  was  held 
at  this  depth  until  the  first  heads  appeared,  when  it  was  applied  to 
a  depth  of  four  inches  and  maintained  there  until  the  rice  was 
ready  to  be  drained.  This  scheme  is  said  to  hasten  the  maturity  of 
the  rice  in  the  southern  states,  but  apparently  has  no  appreciable 
effect  here. 


270  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION 

In  order  to  determine  the  maximum  and  minimum  temperatures 
of  water  at  the  various  depths  of  submergence,  records  were  taken 
daily  at  8  a.m.,  1  p.m.,  and  5  p.m.  The  readings  for  the  shallow  depths 
of  water  showed  higher  temperatures  during  the  day  and  lower 
temperatures  during  the  night  than  for  the  greater  depths  of  sub- 
mergence. The  most  uniform  temperature  was  obtained  on  the  plat 
submerged  six  inches  deep.  It  is  probable  the  yields  are  affected  to 
a  considerable  extent  by  the  daily  range  of  temperature. 


SUMMARY 

Approximately  67,000  acres  of  rice  were  irrigated  in  California 
in  1916,  the  water  supply  being  obtained  principally  from  Sacramento 
and  Feather  rivers.  Only  about  3700  acres  were  irrigated  by  pump- 
ing from  wells. 

Land  is  prepared  for  irrigation  in  contour  checks,  preparation 
consisting  mainly  in  making  ditches  and  levees  and  installing  gates. 
The  gates  must  be  wide  enough  to  admit  the  large  heads  of  water 
used  in  the  initial  floodings. 

The  irrigation  season  consists  of  two  periods.  Frequent  light 
irrigations  with  relatively  large  heads  of  water  are  given  to  germinate 
the  seed  and  to  maintain  growth  until  the  plant  is  four  to  six  inches 
high,  and  thereafter  the  land  is  continually  submerged  to  a  depth  of 
six  to  eight  inches  until  the  rice  is  matured. 

Measurements  of  the  use  of  water  in  1916  on  eighteen  typical  fields 
in  Sacramento  Valley  showed  a  range  of  from  4.27  to  14.83  acre-feet 
per  acre,  an  average  depth  applied  of  8.23  feet,  and  an  average  of 
forty-seven  acres  served  per  cubic  foot  per  second.  The  heads  of 
water  used  per  acre  averaged  .052  cubic  foot  per  second  before  sub- 
mergence and  .034  during  submergence.  The  lowest  use  was  on  fields 
with  heavy  retentive  soil,  where  the  preparation  was  good  and  the 
water  carefully  handled.  The  average  annual  use  over  a  three-year 
period  on  a  field  near  Biggs  was  4.60  acre-feet  per  acre.  During 
the  three  irrigation  seasons  the  average  precipitation  was  0.23  foot 
and  evaporation  3.19  feet.  Irrigation  practice  and  requirements  in 
California  differ  from  those  in  the  Gulf  states,  due  mainly  to  different 
climatic  conditions. 

Adequate  drainage  is  essential  to  successful  rice  production. 
Planting  and  harvesting  are  both  delayed  while  the  soil  remains  wet, 
and  the  removal  of  alkali  salts  and  the  relief  of  water-logged  lands 
are  dependent  upon  drainage  facilities. 

The  results  of  experiments  made  in  1914  to  1916,  inclusive,  on 
black  clay  adobe  soil  near  Biggs  indicated  that  thirty  days  after 
emergence  of  the  plant  is  the  best  time  for  commencing  submergence, 
and  that  six  inches  is  probably  the  most  advantageous  depth  of  sub- 
mergence. Very  poor  yields  were  secured  where  no  water  was  held 
on  the  land.  Fluctuating  the  depth  of  water  had  very  little  effect 
on  plant  growth.  More  uniform  temperatures  of  the  water  were 
found  with  the  greater  depths  of  submergence. 


